Excitability of motor and sensory axons in multifocal motor neuropathy

ObjectiveTo assess excitability differences between motor and sensory axons of affected nerves in patients with multifocal motor neuropathy (MMN).MethodsWe performed motor and sensory excitability tests in affected median nerves of 20 MMN patients and in 20 age-matched normal subjects. CMAPs were recorded from the thenar and SNAPs from the 3rd digit. Clinical tests included assessment of muscle strength, two-point discrimination and joint position.ResultsAll MMN patients had weakness of the thenar muscle and normal sensory tests. Motor excitability testing in MMN showed an increased threshold for a 50% CMAP, increased rheobase, decreased stimulus-response slope, fanning-out of threshold electrotonus, decreased resting I/V slope, shortened refractory period, and more pronounced superexcitability. Sensory excitability testing in MMN revealed decreased accommodation half-time and S2-accommodation and less pronounced subexcitability. Mathematical modeling indicated increased Barrett-Barrett conductance for motor fibers and increase in internodal fast potassium conductance for sensory fibers.ConclusionsExcitability findings in MMN suggest myelin sheath or paranodal seal involvement in motor fibers and, possibly, paranodal detachment in sensory fibers.SignificanceExcitability properties of affected nerves in MMN differ between motor and sensory nerve fibers.     

一例X-连锁高IgM综合征合并进行性多灶性脑白质病的基因变异分析

目的对1例临床拟诊为X-连锁高IgM综合征(X-linked hyper-IgM syndrome,XHIM)并发进行性多灶性脑白质病变(progressive multifocal leukoencephalopathy,PML)的患儿CD40L基因及人类嗜神经多瘤病毒(Jamestown Canyon virus,JCV)进行检测,明确致病原因,为临床诊断提供依据。方法采集患儿及父母外周血提取基因组NDA,设计扩增CD40L基因5个外显子及外显子-内含子连接区的特异性引物并进行PCR扩增,产物测序结果与GenBank中CD40L基因序列分析对比确定有无变异。用两对JCV特异性引物对患儿外周血DNA行巢式PCR扩增,目的条带PCR产物测序结果与GenBank中JCV序列对比确定患儿是否存在JCV感染。结果测序结果显示患儿为CD40L c.506 A>C(p.Tyr169Ser)错义变异半合子,该变异位于CD40L肿瘤坏死因子同源区结构域,引起CD40L蛋白疏水作用及结构稳定性丧失,经PolyPhen2及SIFT蛋白功能预测软件预测分别为很可能有害变异(probably damaging,score=1.00)及有害变异(deleterious,score=-8.868),该变异尚未见文献报道。患儿母亲携带CD40L c.506 A>C(p.Tyr169Ser)半合子变异,父亲未检测到该变异。患儿外周血DNA巢式PCR产物经凝胶电泳后发现JCV目的条带,测序结果与GenBank中JCV基因序列比对同源性达到99%,表明患儿外周血DNA中含有JCV,有JCV感染。结论CD40L基因分析及JCV检测结果确诊患儿为XHIGM,其并发的PML与JCV感染有关。     

Management challenges for chronic dysimmune neuropathies during the COVID-19 pandemic

Since March 2020, the COVID-19 pandemic has led to the need to re-think the delivery of services to patients with chronic dysimmune neuropathies. Telephone/video consultations have become widespread but have compounded concerns about objective evaluation. Therapeutic decisions need, more than ever before, to be considered in the best interests of both patients, and society, while not denying function-preserving/restoring treatment. Immunoglobulin therapy and plasma exchange, for those treated outside of the home, expose patients to the hazards of hospital or outpatient infusion centers. Steroid therapy initiation and continuation pose increased infectious risk. Immunosuppressant therapy similarly becomes highly problematic, with the risks of treatment continuation enhanced by uncertainties regarding duration of the pandemic. The required processes necessitate considerable time and effort especially as resources and staff are re-deployed to face the pandemic, but are essential for protecting this group of patients and as an integral part of wider public health actions.     

Progressive multifocal leukoencephalopathy after liver transplantation can have favorable or unfavorable outcome

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC polyomavirus (JCPyV) in immunocompromised patients, including solid organ transplant recipients. We report 2 cases of PML late after liver transplantation (144 and 204 months) and review the few other published cases. The clinical course of PML is characterized by a rapid progressive neurological decline coinciding with the presence of white matter lesions on magnetic resonance images. No direct antiviral therapy is available against the JCPyV. The prognosis is therefore extremely poor. Restoration of the immune response achieved by tapering or ending the immunosuppressive therapy is the basis of treatment in transplanted patients. One of our patients is alive 3 years after diagnosis after total withdrawal of immunosuppressive therapy. The other presented severe rejection when tapering immunosuppression and died 26 months after diagnosis.     

A Novel Segment Classification for Multifocal and Multicentric Breast Cancer to Facilitate Breast‐Conservation Treatment

Breast conservation treatment (BCT) is an appropriate alternative to mastectomy for the treatment of unifocal breast cancer. Multifocal and multicentric breast cancers (MFMCBC) challenge conventional indications for BCT and are often treated with mastectomy. Following progress in treatment strategies for unifocal tumors, there was a movement to evaluate the use of BCT for MFMCBC. Now a growing body of evidence from retrospective data has emerged, demonstrating acceptable local control and overall survival rates with BCT for MFMCBC. Prospective studies are needed to confirm these findings. One of the possible barriers to such trials is the absence of a standardized classification and nomenclature for MFMCBC at this point in time. A novel segment classification is presented in this article in an endeavor to overcome this deficiency and allow future work on this issue.